1. Field of the Invention
This invention relates to a processing liquid supply unit for supplying a processing liquid used in processes such as adhesion in the manufacturing of semiconductor devices, for example.
2. Description of the Related Art
In a process in which desired processing is performed using a processing liquid, for example, the adhesion process for promoting adhesion between a wafer and a photoresist in the manufacture of semiconductor devices, a processing liquid is supplied to semiconductor wafers set in the processing apparatus in semiconductor manufacturing equipment in a clean room.
Conventionally, such a processing liquid is stored in a storage tank provided inside or adjacent to semiconductor manufacturing equipment and is supplied from the storage tank to semiconductor wafers. An alarm is provided which is arranged such that it is activated when the stored amount of the processing liquid in the tank is consumed by processing of the wafers and decreases below a specified amount. On being notified of the activation of the alarm, the operator enters the clean room and changes tanks. Further, he performs preliminary operations such as refilling the replaced storage tank with a specified gas.
However, the tank changing operation requires a long period of time. When the operator changes storage tanks, the downtime of the semiconductor manufacturing equipment is long. This is not desirable from the viewpoint of keeping the cleanliness of the clean room; for when the operator enters the clean room, he brings dust in. Also, he may be endangered since some kinds of processing liquids are harmful to the human body.